The present invention relates in general to digital imaging. In particular, the invention relates to a method and system for image matching.
Image matching is a fundamental technique used in applications like computer vision, object recognition, motion tracking, 3D modeling, etc. Image matching is performed to check whether two images have the same visual content. However, the two images need not be exactly the same. For example, one image may be rotated or taken from a different viewpoint as compared to the other image, it may be a zoomed version of the other image, or there might be distracting elements in the image. Furthermore, the two images may be taken under different lighting conditions. Despite such variations in the two images, they contain the same content, scene or object. Therefore, various image matching techniques are used to match images effectively.
In an example scenario, image matching may be performed to identify one or more matches against a query image provided by a user. The query image provided by the user can be, for example an image of a movie poster, a picture of an outdoor holiday spot, a photograph of a famous personality, etc. Furthermore, a server, for example a personal computer or any data processing unit that is present in a communication network, can include a database of thousands of images from a number of sources such as magazines, posters, newspapers, the Internet, billboard advertisements, etc. The query image from the user can be matched against the images stored in the database to identify appropriate matching images corresponding to the query image.
Presently, there are service providers that help a user to identify one or more matching images for a query image. In one such case, a user may click a photograph from a communication device, for example a mobile phone with an inbuilt camera, and send it to a server for image-search.
Presently, centralized servers are used for image matching application. The database of all reference images which can be used for matching is maintained at one central server. The probability of identifying one or more correct matches for a query image depends on the number of reference images which can be used for searching and is stored at the server. However, in case of a centralized server, since a single image database is used to store all the reference images, the image-search is restricted to the single database. Also, due to limited storage space of the centralized server and given the large file size of the images, there is a restriction on the maximum number of reference images that can be stored at the centralized server. Further, a problem may arise when the number of query images received at the centralized server is more than the number of searches the centralized server can handle at a given time. The capacity of searches may be restricted due to limited hard drive space, memory, and processing speed of the centralized server. In such a situation, the query images may be queued, resulting in longer wait for a user to get one or more matching images for a corresponding query image.